The goal of this contract is to provide support of National Toxicology Program (NTP) hazard identification (or hazard assessment) activities targeted toward the prevention of diseases or adverse effects caused by environmental exposure to chemical or physical agents. This project involves the prechronic study of cumene hydroperoxide and prechronic and chronic studies of 3-picoline, dimethyl-p-toluidine, ginkgo biloba and pyrogallol. The 90-day studies for all test articles are completed and study reports have been received. The 2-year studies of 3-picoline, DMPT, pyrogallol and ginkgo biloba have been completed and reported. The 2-year studies of cumene hydroperoxide were canceled Keywords Carcinogenicity; toxicity; bioassay; F344 rats; B6C3F1 mice; 3-picoline; cumene hydroperoxide; N,N-dimethyl-p-toluidine; ginkgo biloba; pyrogallol.